Conventionally, in the field of paint, adhesive, and coating, a resin composition including a base component and a curing agent is known, and for the curing agent, for example, a carbodiimide curing agent is known.
To be more specific, for the carbodiimide curing agent, for example, Patent Document 1 (Synthesis Example 82) below has proposed a polycarbodiimide composition produced by reaction of 673 g of hexamethylenediisocyanate (HDI), and 800 g of polyethylene glycol monomethylether having an average molecular weight of 400 at 120° C. for 1 hour, and by further adding 13.5 g of a carbodiimide-formation catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide), and further allowing the mixture to react at 185° C. for 5 hours.
By drying and curing such a resin composition composed of a polycarbodiimide composition (curing agent) and a base component, a cured resin such as coating can be produced.